Quantifying and Addressing Parameter Indeterminacy in the Classical Twin Design
نویسندگان
چکیده
منابع مشابه
Quantifying and addressing parameter indeterminacy in the classical twin design.
The classical twin design (CTD) is the most common method used to infer genetic and environmental causes of phenotypic variation. As has long been acknowledged, different combinations of the common environment/assortative mating, and additive, dominant, and epistatic genetic effects can lead to the same observed covariation between twin pairs, meaning that there is an inherent indeterminacy in ...
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The classical twin design (CTD) circumvents parameter indeterminacy by assuming (1) negligible higher-order epistasis; and (2) either nonadditive genetic or common environmental effects are nonexistent, creating two potential sources of bias (Eaves et al., 1978; Grayson, 1989). Because the extended twin-family design (ETFD) uses many more unique covariance observations to estimate parameters, c...
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Statistical power of the classical twin design was revisited. The approximate sampling variances of a least-squares estimate of the heritability in a univariate analysis and estimate of the genetic correlation coefficient in a bivariate analysis were derived analytically for the ACE model. Statistical power to detect additive genetic variation under the ACE model was derived analytically for le...
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The developments in physics since the early decades of this century have shown that our physical world is not completely empirically deterministic, that is, the motion of a mechanical system cannot be fully determined from physical measurements of the initial positions and velocities of its points. In particular, chaos theory has shown that infinite precision is required in the measurements of ...
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ژورنال
عنوان ژورنال: Twin Research and Human Genetics
سال: 2005
ISSN: 1832-4274,1839-2628
DOI: 10.1375/twin.8.3.201